Dynomotion

Group: DynoMotion Message: 5231 From: michaelthomasn Date: 6/16/2012
Subject: Thread grinding
Hi Tom,

Currently all is going well with the Studer grinder conversion.

My friend would now like to add an encoder to the servo that is used as the spindle....making it into a c axis.

The grinder is basically like a lathe except there is a grinding wheel where the tool post would be.

The need for the c axis is so that he can grind threads on this machine.

Unlike a lathe.....threads are ground by first plunging the formed wheel into the stock, then rotating the c axis in coordination with the x for the proper pitch at maybe 2 rpm.....then stopping after a set number of rotations and retracting the x. The c and x would reposition back to where they started, and the process would repeat until the necessary depth is achieved. The thread grind process begins and ends with the c axis stopped.

Does this sound reasonable to you?

It seems as though it is actually simpler than a lathe since its not syncing up at speed.

I wonder how the c would be commanded to turn more than 1 rotation since it would be an angular axis, though.

Mike
Group: DynoMotion Message: 5233 From: Tom Kerekes Date: 6/17/2012
Subject: Re: Thread grinding
Hi Mike,

That sounds very reasonable.  I think it fits more the model of a rigid tap operation rather than a single point thread operation.  Where the Spindle axis is moved a certain number of revs while another axis (usually referred to as the Z axis) is coordinated with it's motion.  Rigid tapping is performed by a KFLOP C program so it can be called from either Mach3 or KMotionCNC. Here is an example from Mach3:

http://dynomotion.com/Help/Mach3Plugin/Mach3RigidTapping.htm

Regards
TK


Group: DynoMotion Message: 5236 From: Michael Niksch Date: 6/17/2012
Subject: Re: Thread grinding
I think I get it.

So right now I have the spindle operating in open loop via a DACOut command to attain the desired rpm.......after setting the the spindle up as an axis in kmotion, will I then command standard S (rpm) for doing normal non-thread work speed by using a Jog instead?

Mike

On Sun, Jun 17, 2012 at 4:35 AM, Tom Kerekes <tk@...> wrote:
 

Hi Mike,

That sounds very reasonable.  I think it fits more the model of a rigid tap operation rather than a single point thread operation.  Where the Spindle axis is moved a certain number of revs while another axis (usually referred to as the Z axis) is coordinated with it's motion.  Rigid tapping is performed by a KFLOP C program so it can be called from either Mach3 or KMotionCNC. Here is an example from Mach3:


Regards
TK